This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Interferon-beta (IFN-beta;e.g., Rebif) is the most frequently used first-line treatment for relapsing-remitting multiple sclerosis (RRMS). Several studies have shown that the use of IFN-beta produces neutralizing antibodies (NAbs) in a significant proportion of MS patients, which are thought to decrease the bio-availability of IFN-beta and reduce its therapeutic effects. This study will examine whether the addition of steroids (methylprednisolone;MP) to the treatment regime will prevent or decrease the development of antibodies, thus improving the effectiveness of Rebif.